Need help jumping my compressor low pressure switch and testing for voltage

'96 XJ here. My ac's blowing warm air and a chirping sound seems to be coming from the rear of the compressor. Center of clutch doesn't turn when the a/c is turned on. Removed the belt and clutch center turns no problem. Before I start replacing parts I want to rule out possible electrical issues first.

Been told I need to do 2 things.

1- test for voltage at the low pressure switch
2- jump the low pressure switch and see if the compressor runs

I have a multi meter but not much experience with it so a little help getting through this would be a whole lot appreciated.

I think to test the low press switch I need to set my multi on 20 DCV (expecting to see 12v), set the black probe on the body somewhere for the ground, and put the red probe (somewhere?) with the a/c turned on and see what it reads. Where to put the red (+) probe is what I need help with. If anyone has an electrical harness diagram or actual picture either would probably do the trick. Also, I have a '96 FSM and I'm sure the answers in there somewhere I'm just not sure where.

And for the second task...jumping the low pressure switch. I'm sure jumping just means attaching a solid wire between two points and with the a/c turned on see if the compressor starts going. Now where these two points are I don't know. Could I just run a wire from the poss terminal on the battery to wherever it needs to go to power the compressor? If so I suppose all I need help is where to put the 12v power wire into at the compressor. Again an electrical harness diagram or pic seems like what I'm looking for.

Thanks

Are you just trying to check the clutch?

Disconnect the clutch connector, and stick a paperclip in there, then touch it to the posstive batt terminal.

Dont do this for too long, or you could overpressurize your system.

bradleyheathhays said:

'96 XJ here. My ac's blowing warm air and a chirping sound seems to be coming from the rear of the compressor. Center of clutch doesn't turn when the a/c is turned on. Removed the belt and clutch center turns no problem. Before I start replacing parts I want to rule out possible electrical issues first.

Been told I need to do 2 things.

1- test for voltage at the low pressure switch
2- jump the low pressure switch and see if the compressor runs

I have a multi meter but not much experience with it so a little help getting through this would be a whole lot appreciated.

I think to test the low press switch I need to set my multi on 20 DCV (expecting to see 12v), set the black probe on the body somewhere for the ground, and put the red probe (somewhere?) with the a/c turned on and see what it reads. Where to put the red (+) probe is what I need help with. If anyone has an electrical harness diagram or actual picture either would probably do the trick. Also, I have a '96 FSM and I'm sure the answers in there somewhere I'm just not sure where.

Go to section 8W-42 of the FSM. There are wring diagrams of the AC circuits.

Note there will be a Low Pressure Switch and an AC Cycling Switch in compressor clutch circuit. section 8W-90 shows the location of the connectors involved.


And for the second task...jumping the low pressure switch. I'm sure jumping just means attaching a solid wire between two points and with the a/c turned on see if the compressor starts going. Now where these two points are I don't know. Could I just run a wire from the poss terminal on the battery to wherever it needs to go to power the compressor? If so I suppose all I need help is where to put the 12v power wire into at the compressor. Again an electrical harness diagram or pic seems like what I'm looking for.

Thanks

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